Tony had been attempting to give up smoking for several months without success. His therapist made him keep a record of when and where he smoked and from this record ascertained that most of his smoking occurred when he was seated on the sofa talking on the telephone. These antecedent stimuli were such that they obviously facilitated his smoking; as a consequence the therapist instructed him to step outside on the veranda with his portable phone and have a conversation on the phone only when he was standing up.

The identification of antecedent stimuli or events (prior to a target behaviour) is now recognized as an important element in the development of self-control through behaviour modification. Typically these events act as discriminative stimuli and often play a major role in evoking certain behaviours. Sometimes a whole chain of antecedent events can be seen as leading to a specific target behaviour. In order to facilitate behaviour change it is usually important to identify these antecedents and structure your behaviour so as to avoid them. For example, someone who is overweight might prepare single portions of pizza and freeze them so that there is less likelihood of eating a whole pizza at one sitting.